A PET bottle or other plastic bottle (container) can be produced by blow molding a heated preform. A preform for forming a bottle with a cross-sectional shape of a circular shape or other shape with a length in the diametrical direction substantially even in all directions is usually heated so that a temperature distribution of its outer surface becomes substantially even in all directions. As opposed to this, with a bottle with a cross-sectional shape with a length in the diametrical direction not even in all directions, for example, a cross-section of an oval shape or a cross-section of a flat rectangular shape, the elongation in the diametrical direction at the time of blow molding differs according to the direction, so the preform has to be heated at the outer surface so as to obtain a temperature distribution corresponding to the elongation.
In the past, a heating system able to give a suitable temperature distribution to the outer surface of a preform based on the shape of a container after blow molding has been proposed (see Patent Document 1). In this system, bent segments guiding and making a support element supporting a preform move by translational movement and rotating disks driving the support element to rotate are alternately arranged in a heating path region provided in the heating system. Further, by making the support element supporting the preform alternately move through bent segments and rotating disks and making the support element rotate by the rotating disks, the outer surface of the preform is heated relatively uniformly. On the other hand, by the support element moving through the bent segments by translational movement, the region of the preform directly facing the heating devices is heated. By suitably controlling the time of translational motion, the temperature distribution of the outer surface of the preform can be made one suitable for production of a bottle with a cross-section of a length in the diametrical direction not even in all directions, for example, a cross-section of an oval shape or a cross-section of a flat rectangular shape.
Patent Document 1: Japanese Patent Publication (A) No. 2003-526544